Drilling device and method for producing a bore

ABSTRACT

A boring apparatus for producing a bore within a support tube in the ground. The boring apparatus comprises a housing which is introducible into the support tube and is non-rotatably fixable to the support tube, a cutting device for removing ground material, a rotary drive for driving the cutting device in rotation and a feeding device, by way of which a flushing fluid can be fed into a region of the cutting device. Arranged above the cutting device is a receptacle, into which removed ground material is deliverable by way of the flushing fluid. Provided in the receptacle is at least one stirring element for mixing the removed ground material with the flushing fluid. The removed ground material is upwardly dischargeable out of the receptacle together with the flushing fluid by means of a discharging device. The invention also relates to a method for producing a bore in the ground.

The invention relates to a drilling device for producing a bore inside a support tube in the ground and to a method for producing a bore in the ground.

A generic device and a method of such type are known from WO 03/085208 A1. Removed ground material is pumped from a receiving chamber of a housing towards the surface. A liquid is injected at high pressure into the receiving chamber in order to improve the flowability.

EP 1 457 602 A2 teaches a method and a device for producing a foundation element, in which the removed ground material remains directly in the borehole and is mixed in the borehole with liquid by the drilling tool and stirring elements mounted thereon. As liquid a settable suspension is fed so that the mixture mixed in the borehole remains therein and hardens to form a foundation element.

The drilling device comprises a housing which can be inserted into the support tube and fixed in a torque-proof manner on the support tube, a cutting means for removing ground material, a rotary drive for driving the cutting means in a rotating manner and a feed means, with which a flushing liquid can be fed into an area of the cutting means.

In the method a support tube is introduced into the ground, a drilling device is inserted into the support tube and fixed in a torque-proof manner on the support tube, ground material is removed by means of a rotationally driven cutting means of the drilling device and a flushing liquid is fed into an area of the cutting means.

A device and a method for producing a borehole inside or below a support tube are described in U.S. Pat. No. 4,202,416. The drilling device is inserted into the support tube and fixed therein in a torque-proof manner. By means of a rotationally driven cutting means ground is removed that accumulates on a conveyor screw provided above the cutting means. When the conveyor screw is full the entire device is withdrawn from the support tube and the conveyor screw is emptied. Afterwards, the drilling process can be continued. Hence, the method concerned is a discontinuous method.

Drilling arrangements with a drilling device capable of being fixed in a support tube are particularly suitable for producing bores underwater, especially in the offshore area. For instance such devices and methods can be used to anchor carrying structures, such as a wind power station, to the seabed. The drilling device can be introduced from a floating pontoon into the support tube. By means of the drilling device the interior of the support tube and, where applicable, a subjacent area can be drilled out. In this process, the drilling device is supported on the support tube.

The invention is based on the object to provide a device and a method for producing a bore inside a support tube, which enable a particularly efficient borehole production, in which removed ground material can be conveyed out of the borehole efficiently.

According to the invention the drilling device is designed in that above the cutting means a receiving container is arranged, into which removed ground material can be conveyed with the flushing liquid, that in the receiving container at least one stirring element is provided for stirring the removed ground material with the flushing liquid and in that a discharge means is provided, with which the removed ground material can be discharged together with the flushing liquid in the upward direction from the receiving container.

According to the invention the method is designed in that removed ground material is conveyed into a receiving container of the drilling device above the cutting means, that in the receiving container the removed ground material is stirred with flushing liquid and in that the removed ground material is discharged together with the flushing liquid in the upward direction from the receiving container.

A fundamental idea of the invention can be seen in the fact that a drilling device and a corresponding drilling method are provided which permit the continuous production of a borehole inside and/or below a support tube. According to the invention a discharge means is provided for this purpose pursuant to a first aspect of the invention, with which the removed ground material can be conveyed together with the flushing liquid out of the borehole and the support tube respectively, and in particular towards the ground surface. To this end, the discharge means can comprise a line and a pump in particular.

In order to ensure that a mixture of removed ground material and flushing liquid is conveyed as continuously as possible, provision is made according to the invention for a receiving container or stirring chamber, in which removed ground material is stirred or mixed with the flushing liquid by means of at least one stirring element. Through the stirring or homogenizing process, sedimentation of the solids content in the receiving container or stirring chamber is at least prevented to a large degree. This enables an efficient and reliable discharge of the removed ground material by way of the flushing liquid serving as carrier medium. The receiving container with the stirring element can also be referred to as a stirring container.

To fix the housing in a torque-proof manner in the support tube provision is preferably made for a clamping means, with which the housing can be clamped in the support tube. In particular, the drilling device can be clamped or braced on an inner tube wall of the support tube. For this purpose, the clamping means can have at least one clamping cylinder or stamp that can be clamped against the inner wall of the support tube. By preference, several clamping elements are distributed over the circumference of the drilling device.

To implement the drilling process the drilling device is therefore supported on the support tube. The drilling device can be lowered by a rope, e.g. from a crane, into the support tube.

The rotary drive arranged in the drilling device, which can be braced in the support tube, preferably drives a shaft running centrally inside the drilling device. The cutting means is arranged at the lower end of the shaft and driven in a rotating manner by the shaft.

Between the cutting means and the at least one stirring element a conveying means, more particularly a conveyor screw, is arranged for conveying the removed ground material from the cutting means into the receiving container. The conveying means or conveyor screw can be driven in a rotating manner, in particular together with the cutting means. By preference, the cutting means comprises at least one cutting edge which is arranged at the lower end of the conveyor screw or conveyor flight and substantially extends in the radial direction.

For an efficient mixing of the drill spoil and the flushing liquid inside the receiving container the stirring element arranged in the receiving container can be driven in a rotating manner. By preference, the at least one stirring element is arranged on a shaft that is driven in a rotating manner and guided through the stirring chamber. However, the rotationally driven stirring element can basically also be provided on an outer wall of the receiving container. By preference, the receiving container is of cylindrical shape.

The drive of the stirring element can be provided in a particularly efficient way in that the cutting means and the stirring element can be jointly driven by the rotary drive. Thus, a common rotary drive is provided for both the cutting means and the stirring elements. However, in order to allow for different rotational speeds a transmission gear can be provided. Cutting means and stirring element are preferably driven by way of a common shaft.

According to the invention it is furthermore preferred that an upper drill part is provided which can be braced in the support tube and that a lower drill part is provided which is movable with respect to the upper drill part and comprises the cutting means and the receiving container. To produce a bore inside the support tube the upper drill part is clamped in the support tube and the lower drill part, along with cutting means and receiving container, is pressed in the downward direction. Hence, the receiving container with the stirring means is always located at a defined distance to the cutting means. After a certain drilling progress the bracing of the upper drill part is released and the upper drill part follows the lower drill part. Subsequently, the upper drill part is braced once again in the support tube and a further drilling step is carried out.

To move the lower drill part with respect to the upper drill part a crowd cylinder is preferably provided. The crowd cylinder, which is operated hydraulically in particular, presses the lower drill part with drill head against the borehole bottom.

In addition, it is preferred in accordance with the invention that the feed means and/or the discharge means has a telescopic line. The telescopic line can in particular be arranged in the area between the upper drill part and the lower drill part that are movable with respect to each other. Alternatively, the feed and/or discharge line connected to the lower drill part can also be supported in an axially displaceable manner inside the upper drill part.

An especially efficient mixing of the drill spoil with the flushing liquid can be achieved in that in addition to the at least one driven stirring element at least one stationary mixing element which interacts with the stirring element is arranged in the receiving container. For example several stirring elements can be arranged on an internal shaft and several mixing elements can be arranged on an inner surface of an outer wall of the receiving container. By preference, the driven stirring elements and the stationary mixing elements are arranged axially offset to each other, overlapping each other in the radial direction such that a flow induced by the stirring elements is swirled by the mixing elements.

To comminute removed ground material prior to its introduction into the stirring chamber a comminuting means can be arranged below the stirring chamber. In particular, the comminuting means can form a narrow passageway between the cutting means and the receiving container and have a guide and crushing surface for guiding and crushing pieces of rock, which is of conical design in particular and arranged below the narrow passageway. To convey the ground material along the guide and crushing surface the conveyor screw of the conveying means can be attached to the said surface. The comminuting means can be driven by way of the central shaft inside the drilling device.

To comminute removed ground material an upwardly tapering conveying chamber can be formed between the cutting means and the narrow passageway below the stirring chamber. In the tapering conveying chamber a conveyor screw having an upwardly tapering cross section can be arranged.

In a further aspect the invention relates to a drilling rig with a support tube which can be introduced into the ground and a drilling device according to the invention which can be arranged in the support tube. By preference, the support tube can be introduced into the ground, e.g. by being driven or screwed in, before the drilling device is inserted into the support tube. By means of the drilling device ground material can be removed inside and/or below the support tube, in which case the support tube can also be driven gradually further into the ground.

With the method according to the invention the advantages set out on the basis of the drilling device can be achieved. As a result of the efficient mixing with the flushing liquid the removed ground material can in particular be conveyed in a reliable manner out of the borehole, in which case a continuous borehole production is rendered possible over great drilling depths.

In the following the invention is described further by way of preferred embodiments illustrated in the accompanying, schematic Figures, wherein shows:

FIG. 1 a perspective view of a drilling device according to the invention;

FIG. 2 a cross-sectional view of a drilling device according to the invention;

FIG. 3 a cross sectional view of a receiving container with cutting and conveying means according to the invention; and

FIG. 4 a perspective view of a receiving container with cutting and conveying means according to the invention.

Identical elements or those having the same effect are designated throughout all Figures with the same reference signs.

A drilling device 10 according to the invention can be inserted into a support tube, not illustrated, and lowered therein. Usually, the support tube is initially introduced into the ground and, where necessary, anchored and can then be drilled out by means of the drilling device descending in the said tube. The introduction of the support tube into the ground, for instance into the bed of a body of water, can be carried out by means of a suitable and generally known introduction device, such as a pile driving device. The support tube then serves on the one hand for the support of the borehole to be produced and on the other hand as abutment and guide for the drilling device 10 fixed therein.

The drilling device 10 comprises a housing 12 which can be secured or braced at different points in the support tube in order to carry out a drilling process. The housing 12 can be designed as a frame structure that comprises a substantially cylindrical outer contour for insertion into the support tube.

In the housing 12 a shaft 32 is supported in a rotatable manner by way of pivot bearings 33. The shaft 32 is driven in a rotating manner by a rotary drive 26 and drives a drill head with a cutting means 56.

The drilling device 10 comprises an upper drill part 20 and a lower drill part 40 which is supported in an axially displaceable manner relative to the former. On the upper drill part 20 or on the housing 12 of the drilling device 10 a clamping means 22 is provided, by means of which the upper drill part 20 or the housing 12 can be braced in a torque-proof and axially fixed manner in the support tube. The clamping means 22 can comprise hydraulically operated positioning cylinders, by means of which clamping elements can be pressed radially outwards against an inner surface of the support tube.

At an upper end of the upper drill part 20 a rope suspension 24 is provided, by means of which the drilling device 10 can be lowered into and withdrawn from the support tube.

By means of one or several crowd cylinders 30, more particularly hydraulic cylinders, the lower drill part 40 can be moved downwards with respect to the upper drill part 20 so that the lower drill part 40 can be pressed against the borehole bottom once the upper drill part is braced in the support tube.

In its lower area the lower drill part 40 comprises a cutting means 56 for removing or cutting off ground material. Above the cutting means 56 a receiving container 44 is arranged, in which a stirring chamber 45 is designed and, in addition, a conveying means 50 can be arranged. The conveying means 50 serves to convey removed ground material from the cutting means 56 into the stirring chamber 45. The stirring chamber 45 serves to mix the removed ground material with a flushing liquid which is introduced during the drilling process into the borehole, preferably above the cutting means 56.

At its upper end facing towards the upper drill part 20 the lower drill part 40 can have a guide means 42 which is supported on the support tube and thereby ensures reliable guidance of the lower drill part 40 inside the support tube.

In the receiving container 44, which is of cylindrical shape in particular, a stirring means is arranged in an upper area. Basically, the stirring means can be designed as a static mixer but in terms of an improved stirring performance it is preferred that the stirring means comprises stirring elements 46 that are driven in a rotating manner. Below the stirring chamber 45 in a lower area of the receiving container 44 a conveyor screw 52 is located, by means of which removed ground material can be conveyed from the cutting means 56 into the stirring chamber 45.

The rotationally driven shaft 32, which drives the cutting means 56 in a rotating manner, extends centrally through the receiving container 44. In addition, the shaft 32 drives the conveyor screw 52. The stirring elements 46 are arranged on an outer circumference of the shaft 32 and are also rotated with the shaft 32.

On an outer, fixed container wall of the receiving container 44 stationary agitation or mixing elements 48 are arranged in an axially offset manner with respect to the stirring elements 46. Stirring elements 46 and mixing elements 48 overlap in the radial direction so that a particularly efficient mixing can take place inside the stirring chamber 45. Stirring elements 46 and mixing elements 48 are of paddle-shaped design and can also be referred to as stirring paddles or mixing paddles.

To feed the flushing liquid, which can be water in particular, a feed means 60 with a feed line 62 and a conveying means or feed pump 64 is provided. In the illustrated embodiment the feed line 62 runs eccentrically along the drilling device 10 and is of telescopic design. It leads into the receiving container 44 in the area of the conveying means 50 above the cutting means 56. An introductory opening 66 of the feed line 62 is arranged such that the flushing liquid is introduced transversely to the drilling axis into the area of the conveying means 50. The introduction is preferably effected under pressure so that a pre-mixing with the removed ground material takes place as early as in the conveying means 50. The feed pump 64, which is a pressure pump in particular, is arranged in the area of the upper drill part 20.

To discharge the suspension consisting of drill spoil and flushing liquid from the receiving container 44 or the stirring chamber 45 a discharge means 70 having a discharge or suction line 72 and a discharge pump 74, in particular a suction pump, is provided. In the illustrated embodiment the suction line 72 runs centrally inside the drilling device 10 within the rotationally driven shaft 32. A suction opening 76 is provided on the shaft 32 and co-rotates therewith.

To drive the shaft 32 a ring-shaped rotary drive 26 is provided, through which the shaft 32 is guided. The rotary drive 26 is located on the upper drill part 20. The shaft 32 is of telescopic design and has at least two shaft elements which are axially adjustable in relation to each other and are preferably coupled to each other by means of engaging elements 34 for the purpose of torque transmission. The feed line 62 and the discharge line 72 running inside the shaft 32 are also of telescopic design.

The cutting means 56 comprises one or several cutting bars with a plurality of chisels. The cutting bar is in each case installed on a lower end of a screw flight of the conveyor screw 52.

Below the mixing or stirring chamber 45 a stationary crushing or comminuting means 54 is arranged for crushing or comminuting larger pieces of rock. To this end, a narrow passageway 53 is formed below the stirring chamber 45, through which the removed ground material is conveyed by the conveying means 50 into the stirring chamber 45. The narrow passageway 53 has a passage cross section for the removed ground material, which is smaller than a cross section of the stirring chamber 45 and/or a removal cross section on the cutting means 56.

Below the narrow passageway 53 the crushing or comminuting means 54 comprises a conical guide surface 55 which guides the removed ground material towards the narrow passageway 53 and comminutes it where necessary, in particular by interacting with the conveyor screw 52. To this end, the conveyor screw 52 runs along the conical guide surface 55 and is preferably attached to the said conical guide surface 55. As a result, an upwardly tapering conveying chamber is formed along the helical conveyor screw 52, in which larger pieces of material are comminuted or crushed when being conveyed in the direction of the mixing chamber 45. The crushing or comminuting means 54, more particularly the conical guide surface 55, is preferably formed of a hardened material and can also be referred to as a cone crusher.

As shown in the Figures, the crushing or comminuting means 54 can be attached to the rotationally driven shaft 32 and thus be driven in a rotating manner by the shaft 32. In particular, the rotationally driven shaft 32 can extend through the crushing or comminuting device 54. By preference, the conveyor screw 52 is arranged on an outer circumference of the conical crushing or comminuting means 54. To assist the comminuting process a guide means 58 having a further, in particular conical contact pressure or guide surface 59 is arranged on an outer surface lying radially opposite the crushing or comminuting means 54. The conical guide surface 59 is equally formed such that the free cross section for the ground material tapers in the upward direction and is preferably also formed of a hardened material.

The flushing liquid is preferably added to the drill spoil in the area of the conveying means 50 or the conveyor screw 52. The introductory opening 66 or, where applicable, the several introductory openings 66 for introducing the flushing liquid are preferably arranged in the area of the crushing or comminuting means 54, in particular in an outer area lying radially opposite the crushing or comminuting means 54 or the conical guide surface 55.

Furthermore, on the upper drill part 20 an installation means for hydraulic and/or electrical equipment is located. By way of hydraulic and electric lines the drilling device 10 can preferably be connected to corresponding supply units outside the support tube.

By way of the device according to the invention and the method according to the invention the excavation of ground in a support tube anchored to the ground is rendered possible in a particularly efficient manner. The removed ground material is conveyed by means of a conveyor flight away from the cutting means, mixed with a flushing liquid and stirred in a stirring container by means of driven stirring elements in order to prevent sedimentation of the solids content and keep the drill spoil in a floating state. The mixture of drill spoil and liquid is sucked out of the stirring area using a suction pump. This results in a continuous removal of the ground material together with the flushing liquid introduced into the borehole, whereby a continuous excavation of ground is rendered possible over great drilling depths. 

1-11. (canceled)
 12. Drilling device for producing a bore inside a support tube in the ground with a housing which can be inserted into the support tube and fixed in a torque-proof manner on the support tube, a cutting means for removing ground material, a rotary drive for driving the cutting means in a rotating manner, a feed means for feeding flushing liquid, a receiving container which is arranged above the cutting means and into which removed ground material can be conveyed, and a discharge means, with which the removed ground material can be discharged together with the flushing liquid in the upward direction from the receiving container, wherein in that the receiving container comprises a stirring chamber, in which at least one stirring element driven in a rotating manner is provided for stirring the removed ground material with the flushing liquid, between the cutting means and the at least one stirring element a conveying means is arranged, and in that through the feed means the flushing liquid can be fed into an area of the cutting means.
 13. Drilling device according to claim 12, wherein in that a clamping means is provided, with which the housing can be clamped in the support tube.
 14. Drilling device according to claim 12, wherein in that the conveying means arranged between the cutting means and the at least one stirring element is designed as a conveyor screw.
 15. Drilling device according to claim 12, wherein in that the cutting means and the at least one stirring element can be jointly driven by the rotary drive.
 16. Drilling device according to claim 12, wherein in that an upper drill part is provided which can be braced in the support tube and in that a lower drill part is provided which is movable with respect to the upper drill part and comprises the cutting means and the receiving container.
 17. Drilling device according to claim 16, wherein in that a positioning cylinder is provided, with which the lower drill part is movable with respect to the upper drill part.
 18. Drilling device according to claim 12, wherein in that the feed means and/or the discharge means has a telescopic line.
 19. Drilling device according to claim 12, wherein in that in addition to the at least one driven stirring element at least one stationary mixing element which interacts with the stirring element is arranged in the receiving container.
 20. Drilling rig with a support tube which can be introduced into the ground and a drilling device according to claim 12 which can be arranged in the support tube.
 21. Method for producing a bore in the ground, in particular by means of a drilling device according to claim 1 and/or a drilling rig according to claim 20, in which a support tube is introduced into the ground, a drilling device is inserted into the support tube and fixed in a torque-proof manner on the support tube, ground material is removed by means of a rotationally driven cutting means of the drilling device, a flushing liquid is fed, removed ground material is conveyed into a receiving container of the drilling device above the cutting means, and the removed ground material is discharged together with the flushing liquid in the upward direction from the receiving container, wherein in that in a stirring chamber of the receiving container the removed ground material is stirred with flushing liquid by means of at least one stirring element driven in a rotating manner, the flushing liquid is fed into an area of the cutting means and in that the removed ground material and the flushing liquid are conveyed into the stirring chamber of the receiving container. 